This invention relates generally to a system for mass termination of multiple signal wires and, more particularly, to keyable connector and header assemblies for that purpose.
Cables composed of multiple signal wires are used extensively in many electronic applications. Particularly popular are both flat and twisted flat ribbon cables that alternate ground wires with signal wires to reduce interwire cross talk. Typically, the conductive wires in these cables are mass terminated in connector units that plug into mated header units on a circuit board. Often systems utilize many pairs of identical connector-header assemblies mounted in closely spaced relationship to each other. Consequently, care must be exercised to prevent engagement between disassociated pairs of assemblies. Such engagement would produce misconnection of signal wires and result in a circuit dysfunction.
The technique currently employed to prevent mismatching of header and connector assemblies entails the modification of the contacts utilized therein. For example, plugging a female contact in a given position on a particular connector will prevent its entry into any header having a male pin contact in a corresponding position. However, engagement with an associated header can be accommodated after removal therefrom of a male pin contact in the corresponding position. By appropriately selecting unique patterns of such contact plugging and pin removal, individual pairs of connectors and headers can be keyed for exclusive mating. Although eliminating problems of misconnection, the contact modification method exhibits the disadvantage of sacrificing contacts that could otherwise be dedicated to signal wires. In addition, contact modifications are not highly visible which sometimes leads to damage during inadvertent attempts to force engagement between mismatched assemblies.
The object of this invention, therefore, is to provide an improved connection system in which each of a plurality of individual connector units can be uniquely keyed for mating with only one of a plurality of individual header units.